Propulsion and steering unit for boats



June 26, 1962 c. J. DAHLE 3,040,696

PROPULSION AND STEERING UNIT FOR BOATS Filed April 8, 1960 5Sheets-Sheet 1 INVENTOR.

Char/es J. Oak [6 June 26, 1962 HLE PROPULSION AND STEERING UNIT FORBOATS 3 Sheets-Sheet 2 Filed April 8, 1960 INVENTOR. 6/2ar/es J; ,Da/z/eM June 26, 1962 Q DAHLE 3,040,696

PROPULSION AND STEERING UNIT FOR BOATS Filed April 8, 1960 3Sheets-Sheet 3 INVENTOR.

C/zar/as J. Da/z/e BY M United States Patent 3,943,696 PROPULSION ANDSTEERING UNIT FOR BOATS Charles J. Dahle, Salmon, Idaho Filed Apr. 8,1950, Ser. No. 20,921 3 Claims. (Cl. 115--16) This invention relates toa novel propulsion and steering unit for use in boats, wherein water isforced through the unit and ejected through a nozzle to providepropulsion, with a rudder located within the resulting stream to providesteering control.

It is an object of this invention to utilize an auger-type impeller toforce water through the stern nozzle with high elficiency and lowturbulence. It is a further objectto design a water-jet propulsionsystem which will maintain the nozzle above the water line during use,but will allow the nozzle to slip below the water level at rest so as tomaintain the priming of the pump unit while at rest.

It is another object of this invention to provide a safe pump unithaving no outside moving parts within the boat. This unit is precisiondesigned and has adjustably positioned bearings for the impellerassembly. The unit is readily adaptable to any size boat and can beinstalled in new or already existing models with equal case.

These and still further objects will be evident from a study :of thefollowing description and the accompanying drawings which illustrate apreferred form'of my invention. It is to be understood at the outsetthat this embodiment is not the only possible form within the scope ofthe invention, but is merely a practical example of its application.

In the drawings:

FIGURE 1 is a fragmentary perspective view of the unit with portions ofthe housing being broken away to show the interior parts;

FIGURE 2 is a fragmentary top view of the unit with portions of the hulland transom being broken away;

FIGURE 3 is a sectional view out along line 3-3 in FIGURE 2;

FIGURE 4 is an end view of the unit as seen from the left in FIGURE 2;

FIGURE 5 is a sectional view taken along line 5-5 in FIGURE 3;

FIGURE 6 is a fragmentary end view of the transom and unit as seen fromthe right in FIGURE 2; and

FIGURE 7 is a sectional view taken along line 7-7 in FIGURE 3.

Referring now to the drawings, there is illustrated an exemplary form ofthe invention adapted to be installed in conventional boats. The pumpunit, generally designated as 10, is positioned directly above the keelline of the boat hull l1 and protrudes through the transom 12 of theboat. A rudder assembly, generally designated as 13, is attached to therear end of the pump unit and is used to control the steering of theboat.

The intake area of pump unit 10 consists of a grill 14 mounted flushwith the lower surface of hull 11. The grill 14 is framed by a frontvertical wall 15, side walls 16 and 17 and a rear wall 13, all of whichare securely joined and sealed to a surrounding mounting plate 20 whichis formed to the contour of the boat bottom. Plate 20 is secured to thebottom of hull 11 by means of bolts 21. Obviously, plate 20 may besecured to hull 11 by a weld or by any suitable method desired in aparticular application. The front wall of grill 14 has fixed to it arearwardly sloping wall 22 which extends upwardly to form the forwardwall of a box structure. S-loping walls 23 and 24, joined to the top ofwalls 16 and 17 respectively, complete the box and converge into aflanged horizontal mounting plate '25.

outside bearing housing 38.

3,040,696 Patented June 26, 1962 Fixed between the walls 15, 22 and therear wall 13, are two staggered rows of wedge bars 26, which form theactual baflie grill. .The bars 26 are spaced so as to allow water toflow freely between them, but are designed to prevent entry of foreigndebris into the pump unit 10. The grill 14 is a solid unit and is fittedinto the boat from the outside. a

The pump unit '10 comprises a cylindrical shell 27 which terminates in areduced conical nozzle section 23. The forward bottom portion of.cylindrical shell 27 is open and has fixed to it a pair of vertical sidewalls 30, 31, a rear vertical wall 32 and a sloping forward wall 33.These four walls 30, 31, 32 and 33 form a sealed box structure whichterminates in an outwardly extending horizontal mounting plate 34. Plate34 is adapted to be bolted to plate 25 by means of bolts 35 to therebymount the forward end of the pump unit It). An intermediate gasket 36provides an elfective seal between plates 25 and 34 to prevent waterfrom entering the boat interior.

Mounted upon the forward wall 37 ofs-hell 27 is an Housing 38 encloses adouble-taper roller bearing assembly 40 of common construction, adaptedto withstand end thrusts. Supported for rotation is the main shaft 41 ofthe pump unitlt).

. Shaft 41 extends forwardly beyond pump unit 16 and may be connected tothe prime mover unit by any desired means. It may be directly splined tothe motor shaft, or may include a clutch or universal connectiondepending upon the'conditions of use to be encountered.

Shaft 41 extends through an aperture in forward wall 37, which is sealedfrom the interior by a packing gland 42 including a gasket 39. Packinggland 42 effectively serves to seal the interior of the pump unit itfrom the interior of the boat, and is bolted securely to wall 37. Inorder to service packing gland 42, an inspection plate 43 is secured toan angular flat area 44 formed on shell 27. Plate 43 may be locked inplace by any desired means. In the device illustrated, plate 43 isthreaded into an opening cut through area 44. Plate 43 may be gripped byhandle 45 and removed when desired. In order to reduce pressure withinthe pump unit 10 before removing plate 43, a pressure relief valve 46 ofstandard construction, is tapped through the plate 43. By releas ingvalve '46, the priming within unit 10 may be lost in order to enable oneto service or replace packing gland 42 without dismantling the entireapparatus.

The pump unit 10 has mounted within it a two stage impeller consistingof two double flights of anger impellers 48 and 50. Each of these doubleflights is preceded by a row of concave turbulence fins designatedrespectively as 51 and 52. The fins in each row are arrangedsymmetrically about the inner circumference of the shell 27. Each fin isinserted within the shell 27 from the outside through correspondingslots, and then sealed in place by welding. The auger impelle 48 iscomprised of two 360 degree blades 53 and 54 which interlock and whichextend radially to positions adjacent the smooth inner surfaces of shell27. The blades 53, 54 are welded to an enlarged portion 55 formed onshaft '41. The second double flight of impellers 50 is composed ofsimilar blades 56, 57 which are also secured to the enlarged shaft.portion 55.

The rear end 58 of shaft 41 is formed with a reduced diameter and isencased by a housing oil. Housing 60 tightly surrounds shaft 41 at itsforward end, and has a conical rear and terminating in a grease cap 6-1through which grease may be forced into the interior of housing 69.Housing 60 contains a roller bearing 62 which rotatably mounts the rearend 58 of shaft 41. It also contains a grease seal 63 and a water seal64 which protect the bearing assembly. Housing 60 is rigidly supportednuts, the required position of shaft 41 may be accurately maintainedwithin the shell 27.

The conical portion of housing 6%} extends within the conical nozzlesection 28 of shell 27. I Mounted on the inner walls of nozzle section23 are three straight fins 68, 7t), 71, which serve to decreaseturbulence'and. to direct water from the nozzle section 28in a straightrearward how. 7

The nozzle section 28 protrudes through the transom 12 of the boat abovethe water line and is sealed by a surrounding ring 72 bolted to theexterior surface of transom 12. Mounted between two extensions 73, 74extending from conical section 28 in'the rudder assembly 13, a ruddershaft '75 is rotatably carried by extensions 73, 74 and has fixedthereto a butterfly rudder 76 which extends within conical section 28.Shaft 75 has fixed thereto a pulley 77 around which a rope 78 isentrained in the usual manner for controlling the angular position ofthe rudder 76. Rope 78 is guided by two idler pulleys 80, 81 mounted ontransom 12 and the rope is controlled in the normal fashion by means ofa steering mechanism (not shown) mounted in the boat. The top end ofshaft 75 is capped by a stabilizing bar 82 which has a tension spring83, 84 mounted between each of its ends and the transom 12. Spring 83,34 maintain bar 82, and there fore rudder 76, in a straight-ahead centerposition with respect to the conical nozzle section 28.

The operation of the device is as follows. The shaft 41 is turned by theboat motor at a high rate of speed. The turning impellers 4S and 50 drawwater through grill 14 and direct it under pressure through the nozzlesection 28 where it is forcibly ejected from the boat. The reaction fromthis ejection propels the boat in a forward direction. The speed of theboat may be controlled by controlling motor speed.

When brought'ito rest, the open end of section 28 will slip below thewater surface due to the boat weight. This will maintain the shell 27full of water, thereby removing any need for subsequent priming. Thespeed of the boat when traveling will create a slip stream of waterbelow the transom, which will maintain section 28 above the water linewhen the boat is in motion. The low draft of this arrangement isparticularly advantageous in rocky or shallow waters Where a propellerdriven craft would be impractical. Furthermore, by placing the entiremechanism above the water line, the consequent drag on the boat isgreatly reduced when compared to conventional marine propelling andguiding systems.

The rudder assembly 13 serves to direct a portion of the ejected waterfor steering purposes. When a hard turn is desired, rudder 76 is turneduntil it contacts shell 27 and thereby cuts off a portion of the nozzlearea. This results in a pressure boost in the outlet stream directed inthe direction opposite to the desired direction of turn. The resultingturn is therefore quickly carried out without disturbing the motorsettings.

An important feature of the use of auger-type impellers is the fact thatthey are able to pump sand and gravel without serious damage to theblades other than normal wear. may come through the grill. Instead, thesand or gravel will merely be pushed rearwardly in a smooth flow ofwater. This feature is particularlyadvantageous when negotiating overshallow sand bars or near shallow beaches.

A boat equipped with this unit is extremely versatile. Full control isafforded by varying the speed of the motor and controlling the rudderposition. For reverse motion, the input shaft rotation maybe reversed byany standard transmission means. Water will then be sucked into thenozzle and ejected through the grill by the impeller blades.

The blades will not fling such fine articles which.

without deviating from the instant invention.

Being symmetrical, the auger blades may act in either direction.

A final benefit of the auger blades is the reduction of cavitationlosses over impellers which rely on centrifugal force to pump water.This results in less maintenance and longer impeller life.

The number of impeller flights can be varied to suit motor and boatrequirements in each particularinstance If added pressure is required,more impellers may be added. Various obvious modifications willnecessarily present themselves to one skilled in this art withoutchanging this basic inventive concept as described. Therefore only thefollowing claims are intended as definitions of the scope of theinvention.

Having thus described my invention, I claim:

1. In a propulsion and steering unit for boats, a shell housing locatedwithin the boat in a longitudinal position, said shell housing having aconical nozzle section protruding through the boat transom andterminating in an open end of reduced diameter, an intake grill boxsealed within an aperture cut through the hull along the keel line, saidshell housing having an open forward section adapted to be hydraulicallysealed in communication with said intake grill box, said grill boxincluding spaced longitudinal bars adapted to prevent entry of foreignmaten'al into the shell housing and to reduce water turbulence, animpeller shaft rotatably journalled within said shell housing andextending forwardly thereof, spiral auger impeller means fixed to saidimpeller shaft, and guide means fixed within said shell housing adaptedto direct water axially through said shell housing and through saidconical nozzle section, said guide means comprising concave radial finssecured through slots formed in the shell housing, said fins beingadapted to direct water to the impeller. means in a constant,nonturbulent stream.

2. In a propulsion and steering unit for boats, a shell housing locatedwithin the boat in a longitudinal position, said shell housing having aconical nozzle section protruding through the boat transom andterminating in an open end of reduced diameter, an intake grill boxsealed within an aperture cut through the hull along the keel line, saidshell housing having an open forward section adapted to be hydraulicallysealed in communication with said intake grill box, said grill boxincluding spaced longitudinal bars adapted to prevent entry of foreignmaterial into the shell housing and to reduce water turbulence, animpeller shaft rotatably journalled within said shell housing andextending forwardly thereof, spiral auger impeller means fixed to saidimpeller shaft, and guide means fixed within said shell housing adaptedto direct water axially through said shell housing and through saidconical nozzle section, said impeller means comprising a plurality ofsets of double flight auger blades fixed to the impeller shaft inlongitudinally spaced relation, said guide means being located forwardof each set of blades. 7

3. In a propulsion and steering unit for boats, a shell housing locatedwithin the boat in a longitudinal position, said shell housing having aconical nozzle section protruding through the boat transom andterminating in an open end of reduced diameter, an intake grill boxsealed within an aperture cut through the hull along the peller meanscomprising a first pair of complementary spiral blades mounted on saidimpeller shaft adjacent said open forward section of said shell housing,a second pair of complementary spiral blades mounted on said impellershaft rearward of said first pair of blades, said guide means comprisinga first set of fixed guide vanes located radially about said impellershaft intermediate said first and second pair of blades and a second setof fixed guide vanes mounted on said shell housing rearward of saidsecond pair of blades, each blade of said first and second pair ofblades extending radially from said impeller shaft outwardly to saidshell housing through its circumferential length.

References Cited in the file of this patent UNITED STATES PATENTS1,000,678 Henderson Aug. 15, 1911 '6 1,498,919 Jensen June 24, 19242,636,467 Johnson Apr. 28, 1953 FOREIGN PATENTS 304,476 Italy Ian. 9,1932 658,900 Great Britain Oct. 17, 1951 739,315 Great Britain Nov. 10,1953 782,628 Great Britain Sept. 11, 1957 OTHER REFERENCES pages 70 and71.

